The present disclosure relates to the subject matter disclosed in German Application No. 100 40 224.0 of Aug. 17, 2000, the entire specification of which is incorporated herein by reference.
The invention relates to a machine tool comprising a machine frame, a first work piece spindle disposed on the machine frame with a first work piece receiving means rotatable around a first spindle axis, a second work piece spindle disposed on the machine frame with a second work piece receiving means rotatable around a second spindle axis, said second spindle being arranged to face the first work piece receiving means, whereby the second work piece spindle is movable in relation to the machine frame in a Z direction parallel to the first spindle axis and an X direction transverse to the first spindle axis, a first tool carriage disposed on the machine frame on one side of the first spindle axis and movable at least in the X direction, its position controlled by a machine control, said first tool carriage having a first tool carrier disposed thereon, in which first tools are disposed.
Such a machine tool is known from the prior art: with this machine tool the ability of the second work piece spindle to move in X direction transversely to the first spindle axis is utilized to conduct a machining operation on the reverse side in the second work piece spindle with an additional tool carrier so that a machining operation can be conducted on the front side with a work piece held in the first work piece receiving means, whereby sufficient space is available for said operation and, in addition, the work piece held in the first work piece receiving means can be supported, for example, by means of a tailstock.
The disadvantage of this solution is that optimum utilization of the machining possibilities cannot be achieved thereby.
Therefore, the object forming the basis of the invention is to improve a machine tool, in particular a lathe, of said type in such a way that an optimized work piece machining operation is possible with respect to the support sides.
This object is achieved according to the invention with a machine tool of the type described above in that at least one further tool is provided on the first tool carriage, that in order to conduct a machining operation of a work piece held in the second work piece receiving means with one of the first tools with the at least one further tool simultaneously with a machining operation of a work piece held in the first work piece receiving means, the second work piece spindle is movable, its position controlled by means of a machine control, and consequently may follow the movement of the first tool carriage with a constant relative position, and in addition is movable relative to the first tool carriage in accordance with the provided machining operation of the work piece held in the second work piece receiving means.
Therefore, the advantage of the solution according to the invention is that this permits a simultaneous machining operation of a work piece in the first work piece receiving means and a work piece in the second work piece receiving means, this being made possible by the first tool carrier and the further tool, both of which, however, are located on a joint tool carriage, and the necessary additional axial movement being achieved by appropriate control of the movement of the second work piece spindle, which must still be movable to be able to remove the work piece from the first work piece receiving means of the first work piece spindle for a machining operation on the reverse side with its second work piece receiving means.
This means that according to the invention a still present movability of the second work piece spindle may be utilized in order to simultaneously conduct a machining operation of a work piece on the first side and another work piece on the second side without further tool carriages, so that low production times result thereby with simple construction.
In order to obtain sufficient space for the machining of the work piece held in the second work piece receiving means in relation to the work piece held in the first work piece receiving means, it is preferably provided that the further tool occupying a working position is displaced towards the second work piece receiving means in relation to the first tool occupying a working position so that collisions between the work pieces themselves or the work pieces and a tool provided for the other work piece may be prevented.
A particularly preferred solution provides that a further tool carrier for the at least one further tool is disposed on the first tool carriage, which thus enables a sufficiently large distance to be created between the tools of the first tool carriage and the at least one further tool.
In addition, the tool carrier provides the possibility of moving the further tool into a working position or out of the working position so that further flexibility is obtained as a result.
No further details have been provided with respect to the arrangement of the first tool carrier and the further tool carrier in relation to one another in association with the explanation of the individual embodiments so far. Thus, it is particularly expedient if the further tool carrier is disposed on a side of the first tool carrier facing away from the first work piece spindle in order to have the further tools in a suitable position for a machining operation of a work piece held in the second work piece receiving means, while at the same time the first tools are available in a suitable position for a machining reformat operation of the work piece held in the first tool receiving means.
It is particularly favorable thereby if several further tools are provided which in a working position face the second work piece receiving means, while the first tools in a working position face the first work piece receiving means.
It would be fundamentally conceivable in the framework of the solution according to the invention to construct the first tool carriages to be movable only in X direction and to perform the Z movement necessary for the machining of the work piece in the first work piece receiving means by an ability of the first work piece spindle to move in Z direction, e.g. by a carriage.
However, a particularly expedient solution structurally provides that in addition to the X direction the first tool carriage is movable in a Z direction parallel to the first spindle axis in a manner controlled by the machine control.
No further details have been given so far with respect to the type of arrangement of the tools of the first tool carrier and of the further tool carrier in relation to one another relative to an X direction running transversely to the first spindle axis.
Thus, alternatively or in addition to the solution of the set problem described above, the object according to the invention is also achieved with a machine tool of the type described above in that the first tool carriage is provided with a further tool carrier, and that on the further tool carrier the further tool occupying a working position is at a greater distance from the first spindle axis in all positions of the first tool carriage than the first tool of the first tool carrier occupying a working position.
This solution has the great advantage that as a result of this changed positioning of the tool respectively occupying a working position, it was possible to conduct the machining of the work piece held in the second work piece receiving means with the further tool occupying a working position in a direction transverse to the first spindle axis, preferably displaced in X direction in relation to the machining of the work piece held in the first work piece receiving means.
It is particularly favorable thereby if the distance of the further tool occupying a working position from the first spindle axis is greater than the distance of the first tool occupying a working position from the first spindle axis by more than a maximum possible work piece diameter.
It is even better if this distance of the further tool occupying a working position from the first spindle axis is greater than the distance of the first tool occupying a working position from the first spindle axis by at least twice the maximum possible work piece diameter.
With this definition it is absolutely possible to perform a machining operation of the work piece held in the second work piece receiving means that is displaced in relation to the machining operation of the work piece held in the first work piece receiving means.
However, the aforementioned condition for performing the displaced machining operation may be met by the tool carriers being approximately the same size, but by the extension of the tools occupying a working position beyond the tool carrier being of different size in a direction transverse to the first spindle axis. However, this would necessitate using special tools at least either in the first tool carrier or the further tool carrier.
For this reason, a particularly favorable solution provides that a further tool receiving means of the further tool occupying a working position provided on the further tool carrier is at a greater distance from the first spindle in all positions of the first tool carriage than a first tool receiving means of the first tool occupying a working position provided on the first tool carrier.
This solution ensures that the further tool receiving means of the further tool occupying a working position is already at a greater distance from the first spindle axis than the first tool receiving means of the first tool occupying a working position, and therefore, in principle, the same tools may be used both in the first tool carrier and in the further tool carrier.
The distance of the further tool receiving means of the further tool occupying a working position from the first spindle axis is preferably greater than the distance of the first tool receiving means of the first tool occupying a working position by at least the maximum possible diameter of the work piece, and even better by at least twice the maximum possible diameter of the work piece.
No further details have been given with respect to the structure of the tool carriers in association with the explanation of the individual embodiments so far.
Thus, it would be conceivable within the framework of the solution according to the invention, for example, to construct the first tool carrier carrying several first tools as a linear tool carrier.
However, a particularly favorable solution for the use of several first tools provides that the first tool carrier has a head which can swivel around a first swivel axis in relation to a housing. Such a swiveling head can be a head which can swivel 90xc2x0 or 180xc2x0 in relation to the housing, for example. Such a swiveling head could also be combined with a linear tool carrier.
However, a solution which is particularly favorable for the use of as many first tools as possible provides that the head is a turret head, which is rotatable around a turret axis as swivel axis.
In the same way, the further tool carrier could also be a linear tool carrier, on which a plurality of further tools is disposed.
It is also particularly favorable here for the use of the further tools if the further tool carrier has a head which can swivel around a further swivel axis in relation to a housing, whereby this head may also be a head which can swivel 90xc2x0 or 180xc2x0, for example.
However, it is particularly favorable for the use of a plurality of tools if the head is a turret head, which is rotatable around a turret axis as swivel axis.
If both the first tool carrier is a multiple tool carrier and the further tool carrier is a multiple tool carrier, then these are capable of being selected simultaneously. However, it is even more advantageous if the first tool carrier and the further tool carrier can be selected independently of one another in order to respectively bring one of the tools into working position.
In particular with the solution whereby a swiveling head is provided for receiving the tools, the aforementioned fixture of the distance of the tools from the spindle axis for displaced machining may be simply achieved by the further swivel axis being at a greater distance from the first spindle axis in every position of the first tool carriage than the first swivel axis so that the desired conditions may already be achieved by the arrangement of the swivel axes of on the first tool carriage.
A further possibility of creating the desired conditions with respect to the arrangement of the tools occupying a working position in relation to the first spindle axis provides that the head which can swivel around the further swivel axis has a smaller extension in the radial direction to the further swivel axis than the head of the first tool carrier which can swivel around the first swivel axis, so that the desired positioning of the tools occupying a working position in relation to the first spindle axis may likewise be already achieved by the radial extension.
A particularly favorable solution provides that both the swivel axes and the radial extension of the heads are selected simultaneously, as described above, in order to achieve the desired positioning of the tools at different distance from the first spindle axes.
Only the first tool carriage has been worked from in association with the explanation of the individual embodiments of the solution according to the invention so far.
It is particularly favorable, in particular in order to reduce the operating times by utilizing even more tools, if a second tool carriage with a second tool carrier is disposed on a side of the first spindle axis opposite the first tool carriage. This provides the possibility of working with a total of three tools simultaneously, in which case two tools are in use on one work piece and one tool is in use on the other work piece.
This second tool carrier can carry one tool in the simplest case. However, it is particularly favorable if the second tool carrier carries a plurality of tools.
No further details with respect to the movability of the second tool carrier have been given in association with the explanation of the individual embodiments so far. Thus, it would be conceivable, depending on the type of axes of movement provided for the first work piece spindle, that the second tool carrier is movable in X direction, its position controlled with the machine control, whereby in this case the first work piece spindle would have to be movable in a controlled manner in Z direction.
Another solution provides that the second tool carrier is movable in Z direction, its position controlled with the machine control.
However, a particularly favorable solution provides that the second tool carrier is movable in both X direction and in Z direction, its position controlled with the machine control, since this type of movability of the second tool carrier is favorably complemented by the movability of the first tool carrier likewise in X and Z direction, so that both tool carriers can be used to machine the work piece held in the first work piece receiving means.
Moreover, both tool carriers may, advantageously, also be used to machine the work piece held in the second tool receiving means, at least when the second work piece receiving means with the second spindle axis is disposed so that the second spindle axis is flush with the first spindle axis.
In this case, the construction of the second tool carrier can be achieved in accordance with the possibilities explained in association with the first tool carrier.
For example, the second tool carrier can also be constructed as a linear tool carrier.
However, it is particularly favorable if the second tool carrier also has a head which can swivel around a second swivel axis in relation to a second housing, whereby a particularly expedient solution provides that this head is a turret head, which is rotatable around a turret axis as swivel axis.
It has not been further discussed in association with the explanation of the embodiments so far whether an addition support of the work piece is necessary and how this should be achieved.
In particular when machining shaft parts with a machine tool according to the present invention, it has proved favorable if a movable tailstock, which is movable from an inactive position into an active position coaxial to one of the spindle axes into the working area, is disposed on the machine frame.
This solution has the great advantage that an additional support of the work piece is possible with such a tailstock in the case of shaft parts which either contributes to a higher precision and/or shorter machining times.
It is particularly favorable in this case if in its active position the tailstock is disposed coaxially to the first spindle axis, and thus serves to additionally support a work piece held in the first work piece receiving means.
No further details have been given with respect to the inactive position of the tailstock. Thus, it would be conceivable, for example, to also hold the tailstock in the region of the working area in the inactive position.
However, in order to prevent collisions, it is particularly favorable if the tailstock is disposed outside the working area in the inactive position.
It would be fundamentally conceivable thereby to dispose the tailstock on a carriage, for example, and to move it into the working area by means of a carriage.
However, another particularly favorable solution provides that the tailstock is held on a transfer means disposed essentially outside the working area, so that no substantial negative influence on the working area occurs as a result of the insertion of the tailstock.
It is particularly favorable thereby if the transfer means has an arm supporting the tailstock with which this may be moved into the working area, so that only an insignificant restriction of the machining possibilities occurs in the working area as a result of the tailstock moving into the working area.
It is particularly favorable thereby if the transfer means moves the tailstock from the active position into the inactive position or vice versa along a path running on a side of the first spindle axis lying opposite the first tool carriage, so that for the movement of the tailstock from the active position into the inactive position or vice versa a region of the working area is affected which enables the tailstock to move through the working area as far as possible free from collision.